Thanx audioguru! the circuit seems to be a lttle complicating & bigger in size. Actually i'm looking for a transistor based short circuit with 3.6 dc volt power supply through which i can increase the sensitivity of the mic of a cell phone itself, by which the phone can adopt even the slightest voice around. for one of my experiment i am in need of such a sensitive mic mobile phone. else you can aslo suggest me the cell phone that has the most powerful mic in it as compared to other phones. i'll buy one for this purpose. but better if i get a solution to the first condition(making a cell phone mic powerful). pls help me ASAP. thanx abc :) :) :)